The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 8c855f0720ff006d75d0a2512c7f6c4f60ff60ee Mon Sep 17 00:00:00 2001
From: "Longpeng(Mike)" longpeng2@huawei.com Date: Tue, 2 Jun 2020 15:05:00 +0800 Subject: [PATCH] crypto: virtio: Fix use-after-free in virtio_crypto_skcipher_finalize_req()
The system'll crash when the users insmod crypto/tcrypto.ko with mode=155 ( testing "authenc(hmac(sha1),cbc(aes))" ). It's caused by reuse the memory of request structure.
In crypto_authenc_init_tfm(), the reqsize is set to: [PART 1] sizeof(authenc_request_ctx) + [PART 2] ictx->reqoff + [PART 3] MAX(ahash part, skcipher part) and the 'PART 3' is used by both ahash and skcipher in turn.
When the virtio_crypto driver finish skcipher req, it'll call ->complete callback(in crypto_finalize_skcipher_request) and then free its resources whose pointers are recorded in 'skcipher parts'.
However, the ->complete is 'crypto_authenc_encrypt_done' in this case, it will use the 'ahash part' of the request and change its content, so virtio_crypto driver will get the wrong pointer after ->complete finish and mistakenly free some other's memory. So the system will crash when these memory will be used again.
The resources which need to be cleaned up are not used any more. But the pointers of these resources may be changed in the function "crypto_finalize_skcipher_request". Thus release specific resources before calling this function.
Fixes: dbaf0624ffa5 ("crypto: add virtio-crypto driver") Reported-by: LABBE Corentin clabbe@baylibre.com Cc: Gonglei arei.gonglei@huawei.com Cc: Herbert Xu herbert@gondor.apana.org.au Cc: "Michael S. Tsirkin" mst@redhat.com Cc: Jason Wang jasowang@redhat.com Cc: "David S. Miller" davem@davemloft.net Cc: virtualization@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200123101000.GB24255@Red Acked-by: Gonglei arei.gonglei@huawei.com Signed-off-by: Longpeng(Mike) longpeng2@huawei.com Link: https://lore.kernel.org/r/20200602070501.2023-3-longpeng2@huawei.com Signed-off-by: Michael S. Tsirkin mst@redhat.com
diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c index 5f8243563009..52261b6c247e 100644 --- a/drivers/crypto/virtio/virtio_crypto_algs.c +++ b/drivers/crypto/virtio/virtio_crypto_algs.c @@ -582,10 +582,11 @@ static void virtio_crypto_skcipher_finalize_req( scatterwalk_map_and_copy(req->iv, req->dst, req->cryptlen - AES_BLOCK_SIZE, AES_BLOCK_SIZE, 0); - crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine, - req, err); kzfree(vc_sym_req->iv); virtcrypto_clear_request(&vc_sym_req->base); + + crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine, + req, err); }
static struct virtio_crypto_algo virtio_crypto_algs[] = { {